Empire-builder has trouble besieging dry area (6)
I believe the answer is:
attila
'empire-builder' is the definition.
Both the definition and answer are singular nouns.
Perhaps they are linked in a way I don't understand?
'trouble besieging dry area' is the wordplay.
'trouble' becomes 'ail' (synonyms).
'besieging' means one lot of letters goes inside another.
'dry' becomes 'tt' (abbreviation for teetotal).
'area' becomes 'a' (maths abbreviation).
'ail' enclosing 'tt' is 'attil'.
'attil'+'a'='ATTILA'
'has' acts as a link.
Can you help me to learn more?
(Other definitions for attila that I've seen before include "Warrior" , "King of the Huns, d. 453" , "Hunnish conqueror" , "A very great Hun of old" , "Great king of the huns" .)